The present invention relates to opening/closing control of a shutter for switching between an information display state and a display shutout state of, for example, a liquid crystal display panel as an information display section of small electronic device, and more particularly to technology for reducing the power consumption of an entire system in a display shutout state.
An opening/closing shutter device for opening and closing an information display section of small electronic device such as a wrist-watch into an information display state and a display shutout state is conventionally available on the market, but such devices mostly employ a mechanical structure. Even if electronics is employed, a complex link mechanism is driven by a motor as a drive source, and an opening/closing shutter is opened and closed by a complex switch mechanism as an operating member for controlling opening and closing.
However, the opening/closing shutter device of the conventional small electronic device described above drives the complex link mechanism by the motor as the drive source and opens and closes the opening/closing shutter by the complex switch mechanism as the control member for the opening/closing control and requires a high power consumption. Especially, when the opening/closing shutter device is adopted for a wrist-watch and put on an arm, the opening/closing shutter device is positioned at the upper part of the wrist-watch body. Therefore, the watch is large in thickness, heavy and not easily fitted on an arm. It is also necessary to decrease the power consumption because such a small electronic device as a wrist-watch is limited to using a small button type battery.
The present invention was achieved in order to remedy the problems described above. It is an object of the invention to provide a small electronic device having a small and lightweight opening/closing shutter, the system as a whole having small power consumption.
In order to achieve the above-object, the small electronic device according to the present invention comprises an information generating means, a display drive means for outputting a display drive signal according to a signal from the information generating means, and a display device for displaying information according to an output signal from the display drive means, which is characterized by a display shutout control means for switching between a display state of the display device displaying information and a display shutout state where the information display by the display device is not visible, a shutter means which is driven by the display shutout control means to form a display shutout state, and the display drive means which stops the operation according to the control by the display shutout control means in the display shutout state.
Thus, the small electronic device provided with a display opening/closing shutter can be realized, which can lower the power consumption of the entire system by stopping the operation of the display drive means in the display shutout state and can be fitted on an arm.
A quite high power saving effect can be obtained by setting control time for switching from the information display state to the display shutout state of the display device as desired and stopping the operation of the display drive means in the display shutout state excepting a few seconds of the information display state during which the shutter is kept open.
The shutter means can be a liquid crystal shutter means using liquid crystal, which has the shutter means mounted in the display device. Thus, a power saving effect can be further improved.
A reflective polarizing plate can also be used for the liquid crystal shutter means.
Thus, a display section of the display device in the display shutout state can have a metallic luster by the incident light from an external light source, and display can be carried out in various ways.
Sensing can be carried out by a variety of sensing methods by controlling the display shutout control means in accordance with a signal from the switch means and using a sensor switch in addition to a manual switch for the switch means. It is also possible to use a switch means which is turned on upon receiving a radio signal from a pager or the like.
Information of the information generating means is determined as time information, and the information display section provided on the display device can easily employ the display form of an analog watch with rotating hands for displaying time information according to the time information from the information generating means.
The small electronic equipment is further provided with information restoring means for controlling elapsed time information on the display shutout state between the display shutout state and the time information display state, and the information restoring means is configured to restore the hands of the pointer type watch to the present time according to the elapsed time information in the information restoring means upon restoring to the time information display state, so that a delay caused by the stop of the analog watch can be automatically restored to correct time.
According to the control carried out by the display shutout control means, the information restoring means starts counting when the time information display state is switched to the display shutout state and keeps the counted value obtained when the counting operation is stopped as elapsed time information upon returning to the time information display state, produces a restoration drive signal for effecting the restoring drive according to the counted value, supplies the restoration drive signal to the display drive means, and automatically returns a delay caused due to the stopping of the analog watch to correct time.
The restoration drive signal can quickly restore the analog watch to the correct time as a fast forwarding drive signal having an appearance cycle faster than that of an ordinary drive signal.